1. Field of The Invention
This invention pertains to methods for manufacturing tires containing belts, plies and beads that are for mounting onto a rim as a component of a wheel and in particular to a manufacture of an elastomer tire by injection molding methods where belts, plies and beads as are to be contained within the finished tire are formed into a package and positioned in the mold to receive the elastomer sprayed therein.
2. Prior Art
The present invention is in a new and unique automated process for the manufacture of an elastomer tire where belts, plies and beads, as are to be encapsulated in a tire core. The belts, plies and beads are maintained in a package of the belts, plies and beads encapsulated in a pre-cure elastomer that is formed to have a hardness or derometer rated that allows it to be rolled into thin flat sections, and the package is for fitting in a mold to receive a flow of an elastomeric material therearound. The elastomeric material flow consists of component chemicals that are combined and react, providing an exothermic reaction generating heat to cure the pre-cure elastomer of the package, forming a finished tire. A utilization of the invention in forming an elastomer tire thereby converts what has largely been a hands on skilled labor intensive process, into an automated process that can be performed by even entry level workers. Where, heretofore in earlier tire forming processes, workers sequentially positioned, and bonded together with adhesives, layers of green rubber and fabric around a mandrel, building a tire from the inside out. Which process includes encapsulating beads in the wide wall ends, with the assembly then cooked or vulcanized, under heat and pressure, in a mold, forming a tire. Unique to the invention is a formation of a package of belts plies and beads, and their positioning in a mold to receive a flow of elastomer directed therearound, with for a use of a pre-cured elastomer, the exothermic heat of reaction of the combined chemical that form the elastomer provides for a final curing of the pre-cured elastomer. In forming the package, the pre-cure elastomer sections are laid up over sections of fabric that are positioned at desired crossing angles, forming a sandwich that will become a tire core of belts and plies. The sandwich is then passed between at least one pair of cold rollers that press the sandwich of sections together. Thereafter, the sandwich is shaped by sequential travel through contoured cold rollers to form it to a shape of a tire core, and beads are then fitted to ends of the sandwich opposite sides, with the end edges then rolled therearound, completing the package of belts, plies and beads encapsulated in the pre-cured elastomer. The package is for positioned in a mold to receive an elastomer injected or other wise passed into the mold, flowing therearound and encapsulating the package. Which molding process is preferably a spin casting process where the elastomer components are sprayed into the mold and react together. Heat is produced in an exothermic reaction provided by the elastomer components mixing that reacts with the packaging material, completing the cure of the pre-cure elastomer.
While simple in concept, the process of the invention constitutes a major improvement to the tire industry, with the materials used in tire construction being significantly cheaper than those presently in use and as the process allows for automation of what has formerly been a hand labor intensive process, providing a significant savings in labor costs. Elastomeric solid, pneumatic and non-pneumatic tires have been manufactured for many years as solid rubber tires, with and without cavities, from as early as 1878. For example, a British Patent No. 2,367, shows a solid rubber tire and rim. Also, rubber tires having inner cavities are shown in U.S. Pat. No.'s 450,816; 464,767 and 612,583. Further, a U.S. Pat. No. 1,014,318 shows, in FIG. 1, a solid rubber tire having a center cavity that provides for maintaining the tire between hook ends of a rim. Similarly, tires with cavities are shown included with wheels of U.S. Pat. Nos. 3,948,303 and 5,524,913, that are directed to tire mountings to a rim, and there is no discussion in either patent of a tire manufacturing processes.
Examples of processes for manufacture of solid non-pneumatic tires by spin casting methods that do not involve a packaging of belts, plies and beads are shown in earlier U.S. Pat. Nos. 4,855,096 and 4,943,323 and in U.S. Pat. Nos. 5,906,836 and 6,165,397 that were co-invented by one of the present inventors. Also, an example of a process and apparatus for manufacturing pneumatic tires by spin casting methods are set out in U.S. Pat. Nos. 4,123,496 and 4,199,315, and processes for encapsulating a plastic reinforcing member as part of a wheel and as a ply within a tire formed by injection molding methods are set out in a U.S. Pat. Nos. 4,231,410 and 4,387,070.
None of the above set out patents, however, teach a formation, in a cold rolling process, of a single package. The present process provides, in a cold rolling process, utilizing a pre-cured elastomer, a package wherein are fixed belts, plies and beads for installation into a mold that is to receives an injection of an elastomeric material or foam, forming, in one step, a tire wherein the packaged belts, plies and beads are optimally positioned. The use of the packaged belts, plies and beads thereby providing a tire that is essentially perfectly balance with the belts, plies and beads optimally located therein. The invention uniquely provides for a formation and fitting of a package containing belts, plies and beads, or combination thereof, into a mold to receive an elastomeric materials injected therein to produce, in a single step a finished tire. Nor has a use of a pre-cured elastomer heretofore been employed for containing tire belts, plies and beads to form a package that is to receive an elastomer cast therearound. In practice, the formed tire can be solid, contain a center cavity, be pneumatic or non-pneumatic, and the elastomer can be rubber, urethane, or the like, and the molding precess can be injection molding, spin casing, or a like manufacturing method, within the scope of this disclosure.